Conspiracy charges are among the most potent instruments in the prosecutor’s toolkit. In a conspiracy case, the government need only prove that there was an illegal agreement, even if no crime occurred or could occur (such as in the case of a government sting). The government can also offer evidence of acts by one co-conspirator against another co-conspirator, even if the second co-conspirator played no role in carrying out that criminal act. In addition, the statute makes it easier to try multiple defendants in a single trial, with all of the attendant risks for spillover prejudice, with the statements made in furtherance of the conspiracy by one co-conspirator offered against all of the others, consistent with Federal Rule of Evidence 801(d)(2)(E).

For all of these reasons, it is important for the federal courts to scrutinize how the government charges and proves conspiracy charges. In recent months, the Second Circuit has frequently opined on issues related to the sufficiency of evidence for proving a defendant had the requisite knowledge of a conspiracy. This special series of blog posts aims to synthesize these recent holdings, and outline considerations for defense attorneys who represent individuals charged with conspiracies.

In United States v. Mackey, 143 F.4th 129 (2d Cir. 2025), the Second Circuit (Raggi, Livingston, Robinson) reversed the conviction of a defendant, Douglass Mackey (“Mackey”) for conspiracy to injure citizens in the exercise of their right to vote in violation of 18 U.S.C. § 241 (“Section 241”) on the grounds that there was insufficient evidence to prove that the defendant knowingly agreed to participate in the conspiracy. The Circuit’s reversal based on insufficient evidence is rare, but perhaps not shocking when the facts and circumstances of the case are considered. The government had charged Mackey for conduct that largely took place on the Internet through public posts; commentators, defense groups, and others criticized these charges, contending that the government’s interpretation of Section 241 violated the First Amendment.

Rather than opine on this tense issue—or on the also-heavily-disputed issue of venue, which the defendant claimed was not proper in the Eastern District of New York—the Circuit instead reversed the conviction based on the government’s lack of evidence at trial on the issue of Mackey’s knowledge of the conspiracy. In doing so, the Circuit articulated the potential pitfalls for the government when it charges a conspiracy in which the defendant’s knowledge of that conspiracy is proved through the defendant’s own conduct and circumstantial evidence from the Internet. The Circuit explained that, if it is equally plausible that the defendant engaged in unlawful conduct but did not know of or agree to a conspiracy, the government must offer evidence from which a jury could reasonably conclude that the defendant knowingly conspired, rather than acted independently. Otherwise, the jury is merely left to impermissibly speculate. Per the Circuit in Mackey, if the government offers no evidence to assist the jury on this point, and common sense does not counsel in its favor, the government’s proof is legally insufficient.

This blog post outlines the factual background of this case and the Circuit’s analysis in its opinion. Please see Part II for further discussion of the Circuit’s Mackey opinion.

Background

Back in 2014, 24-year-old Mackey began posting on the social media website Twitter (now known as “X”) under an account with the name “Ricky Vaughn.” In 2015 and 2016, as the 2016 presidential election loomed, Mackey used this Twitter account to post election-related content, largely in support of then-candidate Donald J. Trump and against then-candidate Hillary Clinton. As he would later testify at trial, Mackey considered himself a “troll,” “shitposter,” or “shitlord,” meaning someone who “posts a lot of stuff” to “distract or get the conversation going.” In September 2016, Mackey was tweeting or retweeting “hundreds of times per day,” and had about 51,000 followers.

While much of what Mackey posted on Twitter might be considered false, misleading, derogatory, or even offensive, the government admitted that most of it was perfectly legal political speech. However, the government drew a line when Mackey and alleged co-conspirators “trained their sights . . . on the mechanics of voting.” The government alleged that Mackey and others conspired to make public posts falsely informing likely Clinton voters that they could vote via text (what the Circuit referred to as “text-to-vote memes”). This conduct, according to the government, violated Section 241.

Mackey made three public posts which the government said crossed that line. On November 1, 2016, days before the presidential election, Mackey tweeted a meme that bore similarities to a political advertisement, and which read: “Avoid the line. Vote from home. Text ‘Hillary’ to 59925.” His tweet contained two “hashtags”: #ImWithHer and #GoHillary. Just after midnight on November 2, 2016, he posted a similar meme with the same message in Spanish. Later that day, Mackey retweeted a post from Twitter user nia4_trump, which contained an image of Hillary Clinton and language similar to Mackey’s previous text-to-vote memes, “tagged” Mackey’s Twitter account, and also contained the hashtag #MAGA and #Vote.

Section 241 criminalizes only conspiracies to injure voters—not unilateral conduct. This is unusual, as most conspiracy charges (such as those most often brought under 18 U.S.C. § 371) are conspiracies to commit a particular crime. Therefore, as required under the statute, the government contended that Mackey’s tweets were part of a conspiracy formed in several direct-message groups on Twitter, in which members who appeared to share support for then-candidate Trump and dislike for then-candidate Clinton messaged each other in private groups. These groups were called “War Room,” “Micro Chat,” and “Madman #2.” Mackey was not a member of these groups at all relevant times. But in these groups, at various times, Mackey and other members shared messages, memes, and other content related to the presidential election. At times, Mackey posted memes he downloaded from these groups on his public Twitter account. For example, in 39 of Mackey’s tweets between October 28, 2016 and October 31, 2016, he made posts using the hashtag “DraftOurDaughters,” which was also the subject of discussion in the War Room group on October 27 and 29, 2016.

Members of those groups also discussed posting memes to falsely suggest to supporters of then-candidate Clinton that they could vote via text message in about 12 messages shared in the War Room on October 29, 2016 and October 30, 2016—just days before Mackey posted memes with similar messaging to the public, and during which time Mackey was a member of the War Room. Over 600 messages were exchanged in that group per day during the relevant time period.

In January 2021, the government filed a complaint charging Mackey with conspiracy to “injure, oppress, threaten and intimidate persons in the free exercise and enjoyment of . . . the right to vote” in violation of 18 U.S.C. § 241. Shortly thereafter, a grand jury indicted Mackey for the same crime. Mackey moved to dismiss the indictment on the grounds that venue was improper, that Mackey was denied due process (because he had no fair warning that tweeting false voting instructions would be considered criminal conduct under Section 241), and that Section 241, as applied in the case against him, was unconstitutional under the First Amendment. In a thorough opinion, the U.S. District Court for the Eastern District of New York (Garaufis, J.) rejected Mackey’s arguments and permitted the case to proceed to trial. See United States v. Mackey, 652 F. Supp. 3d 309, 349 (E.D.N.Y. 2023).

In March 2023, the case proceeded to a five-day jury trial before Judge Donnelly. At trial, the government called 19 witnesses, including at least one alleged co-conspirator, a Twitter user going by “Microchip,” who had been a member of the War Room group, and testified pursuant to a cooperation agreement with the government. Mackey testified in his own defense.

The jury began deliberations on March 27, 2023. On March 28, 2023, with the jury unable to reach a verdict, the district court gave a modified Allen charge. On March 29, 2023, after some back and forth with the jury about the state of deliberations, the jury informed the district court that it could not reach a unanimous verdict. Mackey moved for a mistrial. The district court instead gave a full Allen charge, and the jury deliberated further. On March 31, 2023, the jury returned a guilty verdict—five days of deliberation for a five-day trial.

Mackey moved for post-trial relief on various grounds, including the sufficiency of the evidence. After recognizing that the evidence about the Twitter groups was “a little bit confusing,” the district court asked the government for, and the government provided, clarification as to when Mackey was a member of each Twitter group. Ultimately, this clarification appears to have satisfied the district court, because it rejected Mackey’s request for relief, and sentenced him to seven months in prison.

The Opinion

On appeal, Mackey made three arguments: (1) that he did not violate Section 241, let alone violate clearly established law, and the government’s interpretation of the statute violated the First Amendment; (2) that venue was improper in the Eastern District of New York, and the government’s justification for venue—that the data Mackey tweeted passed through the district—was untenable; and (3) that the government’s evidence was insufficient to prove that Mackey knowingly agreed to the unlawful effort. Despite substantial briefing on the subject, including from amici, the panel ignored the hot-button First Amendment issue, as well as the venue dispute. Instead, the panel only addressed Mackey’s sufficiency of the evidence argument, and in doing so, enacted a rare reversal of a jury verdict on these grounds.

Recognizing the rarity of its chosen approach, the Circuit began by noting that the deferential standard applied to the government’s evidence after a jury verdict (i.e. that all inferences be resolved in favor of the government), does not apply to inferences based on conjecture or speculation. In other words, the inferences have to be informed by the evidence and not mere guesswork. Moreover, a conviction cannot survive if the government’s evidence is nonexistent or “so meager as to preclude the inferences necessary” to convict. United States v. Aquart, 912 F.3d 1, 45 (2d Cir. 2018). This case presented that “meager” scenario where even the customary inferences drawing in favor of the government’s theory were insufficient.

In cases charging a conspiracy, typically, “the high degree of deference” afforded to a jury verdict is “especially important” because a conspiracy “by its very nature is a secretive operation,” and
“it is a rare case where all aspects of a conspiracy can be laid bare in court . . . .” United States v. Anderson, 747 F.3d 51, 72-73 (2d Cir. 2014) (emphasis added). The Circuit in Mackey explained that this was that rare case, because the conspiracy, as charged by the government, was planned and executed entirely on the Internet. Indeed, the government did not contend that Mackey communicated off-line with any co-conspirator. The entire conspiracy existed on the Internet and was therefore provable by evidence available on the Internet, which the government could subpoena, and offer at trial. Put simply, in this case, the conspiracy could “be laid bare in court.”

A conviction for involvement in a criminal conspiracy requires proof that the defendant knowingly joined and participated in it. In other words, the government must prove beyond a reasonable doubt that the defendant agreed to the conspiracy’s unlawful purpose. Mere association with the conspiracy is not enough. In Mackey’s case, this meant that the government had to prove that Mackey “knowingly agreed with members of the War Room to injure others ‘in the free exercise or enjoyment of’ the right to vote.” 143 F.4th at 140. The Circuit concluded that the government’s evidence on this point was insufficient, even when viewed deferentially, for several reasons.

First, the government did not present to the jury evidence that Mackey viewed or participated in the War Room’s plan to post the misleading text-to-vote memes. The jury heard evidence that Mackey’s participation in the War Room and other Twitter groups declined as the election neared. In fact, he was not a member of “Micro Chat” group or “Madman #2” group at the time discussions about the text-to-vote memes took place. And while he was a member of War Room during the group’s discussion of the purported conspiracy on October 29 and 30, 2016, the government did not dispute that Mackey’s November 1 and 2, 2016 posts were downloaded from a public website, 4chan, not the War Room group, and the jury heard evidence that Mackey had not been participating in the War Room discussions for approximately two weeks before he posted his text-to-vote memes.

Second, the government did not present any messages or other communication between Mackey and other co-conspirators like Microchip, who testified about the conspiracy’s formation at trial. Microchip also did not implicate Mackey in his testimony—an uncommon type of cooperating witness who is only offered for proof of the conspiracy and not the defendant’s participation in it.

Third, the Circuit concluded the government’s circumstantial proof of Mackey’s knowledge was also insufficient. The government had argued on appeal that circumstantial evidence permitted a jury to conclude that Mackey viewed the direct messages in the War Room group related to the conspiracy, located similar memes elsewhere, and then posted them to his own account. The government argued that because a jury could make these findings, it could also conclude that Mackey knowingly joined the conspiracy. The Circuit explained that, in theory, circumstantial evidence could permit a jury to reach this result. But in this case, the circumstantial evidence offered was insufficient for a jury to do so.

The Circuit explained its conclusion first by noting that the government’s proof primarily involved evidence of Mackey’s own conduct: his actual posting of the text-to-vote memes and his membership in Twitter groups. But, the Circuit explained, the defendant’s conduct will not always, by itself, be highly probative of his knowing participation in a conspiracy, in light of the surrounding circumstances. In other words, the defendant’s actions are not enough; there needs to be proof of the illegal agreement, which is the essence of a conspiracy charge.

So, when is the defendant’s conduct probative of his knowing participation in a conspiracy? The Circuit said that depends on “on a combination of ‘common sense’ inferences and corroborative testimony and circumstances’”—circumstantial proof. 143 F.4th at 141. Whether it is reasonable to infer knowing agreement from circumstantial proof is based on “nature of that proof.” In practice, the inquiry is whether the government’s circumstantial proof rules out a plausible, alternative explanation for the defendant’s conduct, in which he acted independent from, albeit consistent with, the conspiracy.

The Circuit laid out two examples to illuminate this standard. First: an alleged drug conspiracy, like in United States v. Anderson, 747 F.3d 51, 72 (2d Cir. 2014). The Circuit explained that certain types of circumstantial proof are likely to rule out an alternative, lawful explanation for why a defendant was a courier for a drug conspiracy: (1) someone who accepts custody of illegal, valuable drugs is likely to be a trusted member of a conspiracy to distribute those drugs, based on the common sense view that the leaders of the crew would not be likely to provide valuable contraband property to a stranger; (2) someone who follows a co-conspirator to a remote location, on the understanding they would receive significant payment for the object to be delivered (which in truth is illegal drugs), can show knowing agreement as this otherwise would be inexplicable behavior; and (3) testimony from a co-conspirator that only a trusted member of the conspiracy would be involved in either of these actions. See, e.g., v. Anderson, 747 F.3d at 72. This type of evidence—of the defendant’s conduct, how drug conspiracies typically work, and interactions with co-conspirators—substantiates the government’s theory as to the defendant’s knowledge.

Second, conversely: an alleged conspiracy to commit perjury by lying to law enforcement, like in United States v. Bufalino, 285 F.2d 408, 415 (2d Cir. 1960). There, after an alleged meeting of Mafia members, each participant separately explained to law enforcement and/or grand juries that they were in the area to visit a sick friend, attend to business, or accompany another. The government’s theory was that they all came up with this plan together, but “[t]here is nothing in the record or in common experience to suggest that it is not just as likely that each one present decided for himself that it would be wiser not to discuss all that he knew.” Bufalino, 285 F.2d at 415 (emphasis added). To the contrary, the circumstances at the time, including press coverage and government suspicions about Mafia activity, made it reasonable that each participant would come to the independent decision to lie about their whereabouts. Id. And when individuals make parallel, but independent, decisions, there is no illegal agreement and therefore no conspiracy.

The Circuit concluded that Mackey’s case was similar to Bufalino. Mackey’s conduct involved posting memes on the Internet in an attempt to suggest that then-candidate Clinton supporters could vote by text. Mackey was a member of the War Room group at the time it discussed a plan to post text-to-vote memes, and therefore it was possible Mackey had seen the group discussion, and agreed to join their unlawful plan. But it was also possible that Mackey independently decided to post the text-to-vote memes.

The evidence of Mackey’s own conduct was not probative of either possibility, though. While Mackey’s memes were similar to ones being circulated by the War Room group chat, they were not the same memes shared by that group. The text-to-vote memes were available elsewhere on the Internet (like 4chan), where Mackey actually downloaded them. He did not participate in the group’s conversation about the text-to-vote memes. He did not communicate with any co-conspirators outside of the group, either. There was also evidence that the War Room group exchanged 600 daily messages, while the text-to-vote discussion took place over 20 minutes, in about 12 messages. Mackey’s membership alone, therefore, did not permit an inference that he saw the messages.

The government therefore had to offer sufficient evidence for the jury to decide that, between the two possibilities, Mackey did in fact view the War Room discussion and decide to participate with them, thereby knowingly agreeing to join the conspiracy. The government failed to prove this here.

The Circuit first rejected as insufficient the government’s circumstantial evidence that the text-to-vote memes posted by Mackey were similar to those shared in the War Room. The posts differed, according to the Circuit, in material respects (i.e. Mackey’s Twitter avatar bore a “MAGA” hat, and the post he retweeted used a hashtag “#MAGA”), suggesting he had not agreed to the War Room’s decision to imply that the option to vote by text was only available to Clinton supporters.

Second, the Circuit rejected as insufficient the government’s circumstantial evidence that Mackey appeared to admit that he viewed War Room messages on a different subject (posting memes about then-candidate Clinton’s position on drafting women into military service), downloaded, and publicly posted those same memes. The Circuit noted that this was the government’s “closest” evidence to showing Mackey’s knowledge of the text-to-vote scheme, but nevertheless rejected it as insufficient because the two War Room threads occurred on different days, and Mackey was a member of numerous groups, each of which contained hundreds of messages a day.  

Third, the Circuit also rejected as insufficient the government’s circumstantial evidence that Mackey retweeted a post by an account called nia4_trump, which the government claimed supported an inference of an agreement to conspire with both the War Room group members, and with the nia4_trump Twitter user independently. The government admitted nia4_trump was, in fact, not a member of the War Room at the time of Mackey’s posts, and the Circuit said that the act of retweeting the post was not itself evidence about whether Mackey and nia4_trump shared any knowledge, agreement, or understanding about the purpose of the post—let alone a conspiratorial purpose. The Circuit explained that the government “did not and could not argue that every Twitter user who posted or reported text-to-vote memes did so for conspiratorial purpose.” 143 F.4th at 144-45. As some people say (and others dispute), a retweet is not an endorsement.

Ultimately, the Circuit concluded that because there was no evidence from which a jury could determine that Mackey knowingly agreed to act in concert with the members of the War Room or others, instead of simply acting independently, there was insufficient evidence to support Mackey’s conviction for conspiracy under Section 241.